Photocatalytic Isomerization of (E)-Anethole to (Z)-Anethole

Abstract

Natural product (E)-anethole was isomerized to (Z)-anethole in a photocatalytic reaction. For this purpose, a self-designed cheap photoreactor was constructed. Among 11 photosensitizers (organo and metal complex compounds), Ir(p-tBu-ppy)3 led to the highest conversion. Triplet energies of (E)- and (Z)-anethole were predicted theoretically by DFT calculations to support the selection of appropriate photosensitizers. A catalyst loading of 0.1 mol% gave up to 90% conversion in gram scale. Further additives were not required and mild irradiation with light of 400 nm overnight was sufficient. As a proof of concept, (E)- and (Z)-anethole were dihydroxylated diastereoselectively to obtain diastereomerically pure like- and unlike-configured diols, respectively.

Indazole as a Phenol Bioisostere: Structure–Affinity Relationships of GluN2B-Selective NMDA Receptor Antagonists

“…Elimination of water from the alcohols 10a , b led to the trans-configured alkenes 11a , b (Scheme ). Photocatalytic isomerization of these trans-configured alkenes by the method of Korff et al only led to an 8:2 mixture of cis-/trans-configured alkenes. Thus, the isomeric cis-configured alkenes 12a , b were formed by partial hydrogenation of the alkynes 8a , b using the Lindlar catalyst. , Furthermore, the alkanes 13a , b were prepared by complete hydrogenation of the alkynes 8a , b (Scheme ).…”

Non-linear photo-switching in molecular actuators through intra-molecular energy transfer from an electron donating core

“…Cyclohexane, chloroform, and toluene solvents used for the photochemical studies were HPLC grade and also obtained from Sigma-Aldrich. 1 H and 13 C NMR spectra, including the observation of the E,Z isomers and their thermal relaxation were obtained on a Bruker Avance III HD 700 or 500 MHz spectrometer. The 700 MHz spectrometer is equipped with a 5 mm z-axis gradient TCI cryoprobe and the 500 MHz spectrometer is equipped with a 5 mm BBFO probe.…”

“…3,9,10 One of the most sought-after features in bichromophoric molecules is the induction of photochemical reactions at the actuator sections. [11][12][13][14] In general, such kinds of molecular designs decouple light absorption and photochemical outcome in different chromophores, allowing for independent optimization of these properties.…”

Two-photon isomerization properties of donor–acceptor Stenhouse adducts

“…where f is the photon ux, N g is the ground state molecular concentration, and z denes the beam propagation direction. This equation calculates the number of photons absorbed per unit time and unit volume, therefore, the number of molecules excited per unit time and unit volume n (2) is: 47…”

“…For example, these schemes have made it possible to induce the activity of biological systems like ion-channels and enzymes. 1 Such approaches have also served to photo-activate polymerization reactions, 2 and to induce the function of catalysts. 3,4 In these applications, photoinduced isomerization reactions are among the most successful methods to achieve such goals.…”